(i) Technical Field
The present invention relates to a semiconductor device.
(ii) Related Art
A semiconductor device including gallium arsenide (GaAs) is used as a power device for high frequency amplification. An active element such as an FET (Field Effect Transistor) and a passive element are provided on a substrate made of GaAs. The active element generates heat because of operation thereof. It is therefore necessary to release the heat. There is a case where a thickness of a substrate made of GaAs is reduced in order to improve radiation performance of a semiconductor chip. However, the GaAs substrate may be damaged during a handling in a manufacturing process thereof, because the GaAs substrate is fragile. And so, the substrate may be reinforced by a PHS (Plated Heat Sink) and the radiation performance may be enhanced. Gold may be used for the PHS. Japanese Patent Application Publication No. 5-166849 discloses that a PHS made of gold is provided on a lower face of a semiconductor substrate.